138 lines
8.3 KiB
HTML
138 lines
8.3 KiB
HTML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns:MadCap="http://www.madcapsoftware.com/Schemas/MadCap.xsd" MadCap:lastBlockDepth="6" MadCap:lastHeight="94" MadCap:lastWidth="853" MadCap:disableMasterStylesheet="true" MadCap:tocPath="" MadCap:InPreviewMode="false" MadCap:PreloadImages="false" MadCap:RuntimeFileType="Topic" MadCap:TargetType="WebHelp" lang="en-us" xml:lang="en-us" MadCap:PathToHelpSystem="../../../" MadCap:HelpSystemFileName="Default.xml" MadCap:SearchType="Stem">
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<head><title>FREQOUT</title>
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<link href="../../SkinSupport/MadCap.css" rel="stylesheet" />
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<link href="../../Resources/Stylesheets/BSE_Help.css" rel="stylesheet" />
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<script src="../../SkinSupport/MadCapAll.js" type="text/javascript">
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</script>
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</head>
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<body>
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<h1 class="code">FREQOUT</h1>
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<div class="ImagePlusCaption">
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<div class="Col2">
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<p>
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<img src="../../graphics/pgm_icon2.gif" border="0" alt="BS2 icon" title="BS2 icon" />
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<img src="../../graphics/pgm_icon2e.gif" border="0" alt="BS2e icon" title="BS2e icon" />
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<img src="../../graphics/pgm_icon2sx.gif" border="0" alt="BS2sx icon" title="BS2sx icon" />
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<img src="../../graphics/pgm_icon2p.gif" border="0" alt="BS2p icon" title="BS2p icon" />
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<img src="../../graphics/pgm_icon2pe.gif" border="0" alt="BS2pe icon" title="BS2pe icon" />
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<img src="../../graphics/pgm_icon2px.gif" border="0" alt="BS2px icon" title="BS2px icon" />
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</p>
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</div>
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<p style="text-align: right;"><a href="../ExampleTopics/FreqoutEx.htm" target="" title="" alt="" class="MCXref_0" xrefformat="{paratext}">FREQOUT Example</a>
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</p>
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<p> </p>
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</div>
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<p class="clear"> </p>
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<p> </p>
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<p class="PlainText">Syntax: <span class="keyword_in_text">FREQOUT</span> <![CDATA[ ]]><i>Pin</i>,<i> Duration</i>,<i> Freq1 </i>{,<i> Freq2</i>}</p>
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<h2>Function</h2>
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<p class="PlainText">Generate one or two sine-wave tones for a specified duration.
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</p>
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<ul>
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<li value="1"><b><i>Pin</i></b> a variable/constant/expression (0 - 15) that specifies the
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I/O pin to use. This pin will be set to output mode.</li>
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<li value="2"><b><i>Duration</i></b> a variable/constant/expression (0 - 65535) specifying
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the amount of time to generate the tone(s). The unit of time for Duration is
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described in the table below.</li>
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<li value="3"><b><i>Freq1</i></b> is a variable/constant/expression (0 - 32767) specifying
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frequency of the first tone. The unit of <i>Freq1</i> is described in the table
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below.</li>
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<li value="4"><b><i>Freq2</i></b> is an optional argument exactly like <i>Freq1</i>. When specified,
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two frequencies will be mixed together on the specified I/O pin.</li>
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</ul>
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<p class="PlainText">Note: See <a href="SOUND.htm" target="" title="" alt="" class="MCXref_0" xrefformat="{paratext}">SOUND</a> for the BS1.</p>
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<h2>Quick Facts</h2>
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<table width="100%" cellpadding="4" cellspacing="0" border="1">
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<tr>
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<td width="20%" align="center" bgcolor="#CFCFCF"> </td>
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<td width="16%" align="center" bgcolor="#CFCFCF">BS2 and BS2e</td>
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<td width="16%" align="center" bgcolor="#CFCFCF">BS2sx</td>
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<td width="16%" align="center" bgcolor="#CFCFCF">BS2p</td>
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<td width="16%" align="center" bgcolor="#CFCFCF">BS2pe</td>
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<td width="16%" align="center" bgcolor="#CFCFCF">BS2px</td>
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</tr>
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<tr>
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<td align="center" bgcolor="#CFCFCF">Units in <i>Duration</i></td>
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<td align="center">1 ms</td>
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<td align="center">0.4 ms</td>
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<td align="center">0.265 ms</td>
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<td align="center">1 ms</td>
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<td align="center">0.166 ms</td>
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</tr>
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<tr>
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<td align="center" bgcolor="#CFCFCF">Units in <i>Freq1</i> and <i>Freq2</i></td>
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<td align="center">1 Hz</td>
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<td align="center">2.5 Hz</td>
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<td align="center">3.77 Hz</td>
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<td align="center">1.51 Hz</td>
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<td align="center">6.03 Hz</td>
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</tr>
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<tr>
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<td align="center" bgcolor="#CFCFCF">Range of frequency</td>
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<td align="center">0 to 32767 Hz</td>
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<td align="center">0 to 81.917 kHz</td>
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<td align="center">0 to 123.531 kHz</td>
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<td align="center">0 to 49.478 kHz</td>
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<td align="center">0 to 197.585 kHz</td>
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</tr>
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<tr>
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<td align="center" bgcolor="#CFCFCF">Related Commands</td>
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<td align="center" colspan="5">
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<p colspan="5" align="center"><a href="DTMFOUT.htm" target="" title="" alt="" class="MCXref_0" xrefformat="{paratext}">DTMFOUT</a>, <a href="PWM.htm" target="" title="" alt="" class="MCXref_0" xrefformat="{paratext}">PWM</a></p>
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</td>
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</tr>
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</table>
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<h2>Explanation</h2>
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<p class="PlainText"><span class="keyword_in_text">FREQOUT</span> generates one or two sine waves using a pulse-width modulation
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algorithm. The circuits in the figure below work by filtering out the
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high-frequency PWM used to generate the sine waves. <span class="keyword_in_text">FREQOUT</span> works over a
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very wide range of frequencies so at the upper end of its range, those PWM
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filters will also filter out most of the desired frequency. You may find it
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necessary to reduce values of the parallel capacitors shown in the circuit, or
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to devise a custom active filter for your application. </p>
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<center>
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<img src="../../graphics/freqout_sch.gif" width="387" height="385" border="0">
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</img>
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</center>
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<p class="PlainText"> </p>
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<p class="PlainText">Here's a simple <span class="keyword_in_text">FREQOUT</span> command: </p><pre class="BScode" xml:space="preserve">
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FREQOUT 2, 1000, 2500
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</pre>
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<p class="PlainText">On the BS2, this command generates a 2500 Hz tone for 1 second (1000 ms) on
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I/O pin 2. See the table above for timing data on other BASIC Stamp models.</p>
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<p class="PlainText">To play two tones on the same I/O pin at once:</p><pre class="BScode" xml:space="preserve"> FREQOUT 2, 1000, 2500, 3000</pre>
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<p class="PlainText">This will generate a 2500 Hz and 3000 Hz tone (on the BS2) for 1 second. The frequencies will mix together for a chord- or bell-like sound. To generate a silent pause, specify frequency value(s) of 0. </p>
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<div class="Col2">
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<div class="MasterFoot">
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<p MadCap:conditions="BSEconditions.BSEWebHelp (Primary)-INCLUDE"><a href="../../HomeTopics/HomePage.htm">Go to Welcome page</a>
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</p>
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</div>
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</div>
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<div class="Col2">
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<div class="MasterFoot">
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<p style="text-align: right;"><span class="ContactInfoProjectName">BASIC Stamp Help</span> <![CDATA[ ]]><span class="ContactInfoVersion#">Version 2.5.4</span> <![CDATA[ ]]></p>
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<p style="text-align: right;">Copyright © <span class="ContactInfoCompanyName">Parallax Inc.</span></p>
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<p style="text-align: right;"><span class="SystemShortDate">8/8/2012</span>
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</p>
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